When a semiconductor device, such as a metal-oxide-semiconductor field effect transistor (MOSFET) or a MOS resistor, is scaled down through various technology nodes, a high dielectric constant κ (high-κ) dielectric (as compared to silicon dioxide) and a conductive material are used to form a gate structure. Within the gate structure, an adhesion layer is configured to help ensure a uniform adhesion of a subsequent layer on the adhesion layer. The adhesion layer is further used to improve a filling of the subsequent layer in a gate replacement technique, help to reduce voids in the gate structure.